Arthroscopic surgery involves using optical instruments, such as an arthroscope, to visualize an operating field inside or near a joint of a patient. The same instrument or other instruments may be used to perform a surgical procedure in the operating field. Common instruments used in addition to the arthroscope include a trimming instrument for cutting tissue and an irrigation instrument for irrigating the surgical field. Each of the instruments requires its own incision to be introduced into the surgical field; thus, many surgeons prefer to use only a trimming instrument and an arthroscope during arthroscopic surgical procedures.
Arthroscopes are fragile in relation to the forces applied during arthroscopic surgery, so a rigid cannula is placed over the arthroscope to reinforce it. The distal end of the rigid cannula is pointed, usually sharp, and so the rigid cannula can scratch or gouge soft tissue within the operating field. The rigid cannula can also become stuck between bones or cartilage during a procedure. A rigid cannula can also damage metal prosthetics used to replace joints, resulting in a shortening of the useful life of the prosthetic and forcing the patient to undergo additional, painful surgeries to correct the problem.
An additional problem associated with arthroscopic surgery is maintaining a clear surgical field during surgery. Blood and debris can cloud the field, impairing a surgeon's ability to visualize tissue. One method of solving this problem is to use the irrigation instrument to clear the surgical field with saline; however, many surgeons strongly prefer to avoid the additional trauma caused by inserting a third instrument. These surgeons will perform arthroscopic surgeries despite problems with visualizing the surgical field.
A further problem associated with arthroscopic surgery is accidental damage to the arthroscope. The arthroscope is often damaged if the working end of a trimming instrument accidentally strikes the sensitive optical components on the distal portion of the arthroscope. The arthroscope may also be damaged if the arthroscope becomes stuck between bones, cartilage or other tissue and excessive force must be used to free the arthroscope. Arthroscopes are expensive, costing thousands of dollars, so accidental damage to arthroscopes is a significant cost problem. A damaged arthroscope could cause delays during surgery and broken pieces of the arthroscope could be deposited in the surgical field. Both situations are harmful to the patient. Thus, devices and methods are needed to prevent accidental damage to arthroscopes during surgery.